软件工程介绍--英文版

©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide1AnIntroductiontoSoftwareEngineering©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide2ObjectivesTointroducesoftwareengineeringandtoexplainitsimportanceTosetouttheanswerstokeyquestionsaboutsoftwareengineeringTointroduceethicalandprofessionalissuesandtoexplainwhytheyareofconcerntosoftwareengineers©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide3TopicscoveredFAQsaboutsoftwareengineeringProfessionalandethicalresponsibility©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide4SoftwareengineeringTheeconomiesofALLdevelopednationsaredependentonsoftware.MoreandmoresystemsaresoftwarecontrolledSoftwareengineeringisconcernedwiththeories,methodsandtoolsforprofessionalsoftwaredevelopment.ExpenditureonsoftwarerepresentsasignificantfractionofGNPinalldevelopedcountries.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide5SoftwarecostsSoftwarecostsoftendominatecomputersystemcosts.ThecostsofsoftwareonaPCareoftengreaterthanthehardwarecost.Softwarecostsmoretomaintainthanitdoestodevelop.Forsystemswithalonglife,maintenancecostsmaybeseveraltimesdevelopmentcosts.Softwareengineeringisconcernedwithcost-effectivesoftwaredevelopment.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide6FAQsaboutsoftwareengineeringWhatissoftware?Whatissoftwareengineering?Whatisthedifferencebetweensoftwareengineeringandcomputerscience?Whatisthedifferencebetweensoftwareengineeringandsystemengineering?Whatisasoftwareprocess?Whatisasoftwareprocessmodel?©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide7FAQsaboutsoftwareengineeringWhatarethecostsofsoftwareengineering?Whataresoftwareengineeringmethods?WhatisCASE(Computer-AidedSoftwareEngineering)Whataretheattributesofgoodsoftware?Whatarethekeychallengesfacingsoftwareengineering?©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide8Whatissoftware?Computerprogramsandassociateddocumentationsuchasrequirements,designmodelsandusermanuals.Softwareproductsmaybedevelopedforaparticularcustomerormaybedevelopedforageneralmarket.Softwareproductsmaybe•Generic-developedtobesoldtoarangeofdifferentcustomerse.g.PCsoftwaresuchasExcelorWord.•Bespoke(custom)-developedforasinglecustomeraccordingtotheirspecification.Newsoftwarecanbecreatedbydevelopingnewprograms,configuringgenericsoftwaresystemsorreusingexistingsoftware.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide9Whatissoftwareengineering?Softwareengineeringisanengineeringdisciplinethatisconcernedwithallaspectsofsoftwareproduction.Softwareengineersshouldadoptasystematicandorganisedapproachtotheirworkanduseappropriatetoolsandtechniquesdependingontheproblemtobesolved,thedevelopmentconstraintsandtheresourcesavailable.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide10Whatisthedifferencebetweensoftwareengineeringandcomputerscience?Computerscienceisconcernedwiththeoryandfundamentals;softwareengineeringisconcernedwiththepracticalitiesofdevelopinganddeliveringusefulsoftware.Computersciencetheoriesarestillinsufficienttoactasacompleteunderpinningforsoftwareengineering(unlikee.g.physicsandelectricalengineering).©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide11Whatisthedifferencebetweensoftwareengineeringandsystemengineering?Systemengineeringisconcernedwithallaspectsofcomputer-basedsystemsdevelopmentincludinghardware,softwareandprocessengineering.Softwareengineeringispartofthisprocessconcernedwithdevelopingthesoftwareinfrastructure,control,applicationsanddatabasesinthesystem.Systemengineersareinvolvedinsystemspecification,architecturaldesign,integrationanddeployment.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide12Whatisasoftwareprocess?Asetofactivitieswhosegoalisthedevelopmentorevolutionofsoftware.Genericactivitiesinallsoftwareprocessesare:•Specification-whatthesystemshoulddoanditsdevelopmentconstraints•Development-productionofthesoftwaresystem•Validation-checkingthatthesoftwareiswhatthecustomerwants•Evolution-changingthesoftwareinresponsetochangingdemands.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide13Whatisasoftwareprocessmodel?Asimplifiedrepresentationofasoftwareprocess,presentedfromaspecificperspective.Examplesofprocessperspectivesare•Workflowperspective-sequenceofactivities;•Data-flowperspective-informationflow;•Role/actionperspective-whodoeswhat.Genericprocessmodels•Waterfall;•Iterativedevelopment;•Component-basedsoftwareengineering.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide14Whatarethecostsofsoftwareengineering?Roughly60%ofcostsaredevelopmentcosts,40%aretestingcosts.Forcustomsoftware,evolutioncostsoftenexceeddevelopmentcosts.Costsvarydependingonthetypeofsystembeingdevelopedandtherequirementsofsystemattributessuchasperformanceandsystemreliability.Distributionofcostsdependsonthedevelopmentmodelthatisused.©IanSommerville2006SoftwareEngineering,8thedition.Chapter1Slide15ActivitycostdistributionWaterfal